What is the prognosis in this case?

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Details
A psychiatrist is called to see a 64-year-old man after he began screaming that there were strange men in his hospital room. The patient underwent a coronary artery bypass graft (CABG) 3 days previously and
appeared to be recovering without complications. He claims that the previous evening he had seen several men standing in his room by the windows. The patient states that they did not say anything to him but that he was “sure that they were going to hurt [him].” He has never seen anything unusual before, and has no prior history of psychiatric difficulties. The nurses’ notes from the late shift indicate that the patient became agitated and restless, although at times during the evening he was also noted to be disoriented and stuporous. He was not observed in this condition on previous evenings. On a mental status examination, the patient was alert and oriented to person and place, but he thought that the date was several months earlier than it actually was. Otherwise, the results of his mental status examination were normal. No hallucinations or delusions were noted at the time of the examination.
1. What is the likely differential diagnosis?
2. What information in the history supports the diagnosis, and what other information would help to confirm it? 3. What might the important etiological factors be?
4. What treatment options are available?
5. What is the prognosis in this case?